The Use of Ultrasound for Preventing Honey Crystallization

Abstract

The aim of this study was to evaluate the effect of ultrasound treatment for preventing honey crystallization on the physicochemical and microbiological properties of unifloral honey and polyfloral honey. Honey samples without any treatment were used as a control group for comparison. The effect of applying ultrasound treatment was evaluated by studying over time the tendency of crystallization, the rheological properties of honey and chemical and microbiological properties. The parameters analyzed for the two groups of samples (treated and untreated with ultrasound), which did not vary or had small variations during the research were water content, acidity, water activity, glucose, fructose, sucrose, glucose/water ratio, glucose/fructose ratio. The crystallization process was installed in the control samples from the first month of the study, and much later in the treated samples. The color of the untreated samples varied considerably, and the color of the treated ones remained stable or slightly varied. For the control samples, the smallest variation in hydroxymethylfurfural (HMF) concentration was in raspberry honey (5%), and the most significant variation was in honeydew honey (30%). For the treated samples, the largest variation of this parameter was found in tillia honey (127%), and the smallest variation was in rapeseed honey (26%). The microbiological quality was higher for the treated samples. In the ultrasound-treated samples of acacia honey, honeydew honey and grassland honey, yeasts, molds or standard plate counts (SPCs) were undetectable. For control samples, SPC values were <10–50 cfu/g. Ultrasound-treated samples maintained their SPC parameter levels or were thus reduced (<10–20 cfu/g). Yeasts and molds were undetectable or had value between <10 and 10 cfu/g. The yeasts and the molds ranged in the control samples between <10 and 40 cfu/g.

Analytical Rheology of Honey: A State-of-the-Art Review

“…The spontaneous precipitation of glucose at room temperature during storage affects the quality of honey and consumer acceptability. The rate of time dependent crystallization is controlled by water content, presence of nucleation seeds (resulting from the monohydrate form of glucose), degree of supersaturation and viscosity [80,81]. For some mono-floral honeys homogeneous crystallization is a natural event; but for most commercial honeys the formation of crystals may result in phase separation, sedimentation and to the augment of water activity up to levels probably in accordance with microbial fermentative processes [80].…”

“…For some mono-floral honeys homogeneous crystallization is a natural event; but for most commercial honeys the formation of crystals may result in phase separation, sedimentation and to the augment of water activity up to levels probably in accordance with microbial fermentative processes [80]. Modifications in rheological properties of honey resulting from crystallization have been described in the literature [47,[80][81][82].…”

“…The delay of the crystallization phenomena can be induced by thermal processing at 50 • C, which reduces the crystal count and viscosity [82]. However, liquefaction by thermal treatment leads to several harmful reactions and to the formation of food contaminants such as 5-hydroxymethylfurfural (5-HMF) even beyond the legal limit [81,82]. Önür et al [82] studied three Turkish honey varieties (sunflower, cotton, and canola) undergoing different treatments (thermal, ultrasound and high hydrostatic pressure), and evaluated the alterations detected in the physicochemical properties and the formation of 5-HMF.…”

Influence of Stirring Parameters on Creaminess of Spring Blossom Honey Measured by Crystal Size, Whiteness Index and Mouthfeel

“…Most consumers prefer liquid or melt-in-the-mouth creamy honey with small crystals that are not noticeable on the tongue [5,6,[8][9][10][11][12]. There are three possibilities to meet the customers' preferences: delaying or avoiding crystallization, liquefying honey after crystallization or controlling the crystallization process by stirring.…”

“…Pasteurization reduces the activity of several enzymes, particularly invertase, and increases the HMF (5-hydroxymethylfurfural) content, which is undesirable. Recently, methods for preventing honey crystallization based on ultrasound [8,12,17,18] or freezing [19] have been described.…”